Search

With the increase in the production of plastics and their destructive effects on water quality, soil and the health of living organisms, It is necessary to know these materials and their production sources. Meanwhile, wastewater treatment plants are one of the main sources of discharge of microplastics into the environment. In the present study, the frequency of microplastics in wastewater and sediments of Kerman were evaluated. For this purpose, 36 samples of wastewater and sediments are taken simultaneously per month that in each sample, about 30 liters of wastewater was collected from the exhausting of initial deposition in 2021–2022. The percentage of organic materials in these samples was measured by using the hydrogen peroxide digestion method and the amount of microplastics was extracted and analyzed by a density-based separation method with sodium iodide salt. Investigation of microplastic contamination in wastewater sediments was done by the Van Veen Grab method. Separation of samples was performed by using hydrogen peroxide and the number of separated samples were determined by the amount of particles per 100 gram of dry sediment. Then the microplastics were examined in terms of color, shape and size. The results demonstrate that in samples of Kerman wastewater, 3576 microplastics were found, which about 98% were fiber types and about 2% were particle type, the dimensions of most of these particles were between 37–300 µm. In addition, 90% of microplastics found in wastewater were blue. There were about 4864 microplastics in all sediment samples. Of these, about 98% were related to fibers, 18% particles and 0.001% membranous particles. Sediment grading also demonstrate that the particle size of 100–250 µm had the highest frequency with 39%. In this investigation, the frequency of separated microplastics in red, black and blue were 30%, 26% and 22%, respectively. Based on the results of the analysis of the questionnaires, it was concluded that it’s not much needed to study microplastics and their sources of production and dissemination. The present study can provide useful information to get more acquainted with the types of microplastics sources and their classification, to control and monitor these pollutants in municipal wastewater.

In recent years, urbanization has widely been developed and resulted in great loss of natural resources on earth and many other consequences such as temperature rise which exposes the cities to a phenomenon called heat island. Urban heat island (UHI) can be identified and analyzed by thermal remote sensing. In the present study, satellite images of Landsat 7 ETM+ (1999 and 2006) and Landsat 8 (2013 and 2016) were used to retrieve the land surface temperature (LST) of Isfahan in Iran by means of the mono-window algorithm. Analysis of thermal levels showed an increase in the minimum temperature of 2016 compared to 1999. Furthermore, the results revealed that the heat island ratio (URI) in Isfahan in four different years followed a rising trend, moving from 0.16 in 1999 to 0.3 in 2016. The findings of this study indicated that the areas influenced by UHI are often in northern and southern parts of the city where vegetation cover is very sparse, the land is arid, and industrialization and regional settlements are booming.

PAHs (polycyclic aromatic hydrocarbons) in urban areas are usually bound to particles. Concentrations are different in different compartments (airborne particles, street dust, suspended sediments in rivers and channels). This study follows concentrations of PAHs from particles in air to street dust and finally suspended sediments in the city of Tehran, Iran compared to Tubingen, Germany. Data sets are based on own investigations (PAHs on suspended sediments), or taken from literature studies (PAHs in street dust and airborne particles). Based on a cross-comparison of concentrations of PAHs on particles, and their congener distribution patterns, the occurrence, interrelation (exchange and mixing processes), as well as possible dilution processes among PAHs in the different particle classes are disentangled. Results show that for Tehran and Tubingen PAHs in airborne particles are very high (in the range of 500 mg kg−1). However, in street dust and suspended sediments PAHs concentrations on particles are around 100 times lower. Surprisingly concentrations in street dust and suspended sediments are 5 to 10 times lower in Tehran (average 0.5 mg kg−1) than in Tubingen (average 5 mg kg−1). Since it is unlikely that PAHs emissions are lower in the Tehran megacity, an effective dilution of the atmospheric signal by uncontaminated (background) particles is hypothesized. Uncontaminated particles may stem from wind erosion of bare surfaces, construction and sand mining sites or even dust from the desert areas, which are frequent in arid climate in Tehran.

Exposure to toxic metals has been increased during recent decades, especially in megacities where various anthropogenic sources discharge loads of pollution to overcrowded urban districts. Soil as a simultaneous sink and source of metallic pollution is considered as an optimum media for monitoring such pollution. In this study, 41 surface soil samples were collected from a district in south of Tehran megacity. Despite determination of bulk metal concentrations (Ni, Cu, Cr, Zn, Co, Cd, Pb Mn, Fe, Ca and Na), a single-step extraction scheme was used for determination of anthropogenic portions. Enrichment factor and geo-accumulation (Igeo)/pollution (Ipoll) indices were calculated to estimate the enrichment class and degree of contamination, respectively. Except for Cd and Pb, other toxic metals showed no or negligible exceedance of reference values. Descending order of anthropogenic contribution from bulk metal concentrations was detected to be as: Cd > Pb > Mn > Cr > Zn > Co > Cu > Ni. Cadmium and lead were detected by all three indices to be in extreme and moderate/significant classes. Relatively high concentrations of Na were attributed to intense salt spraying for streets deicing during winter time when sampling occurred, while Ca concentrations were justified by geogenic source mainly dominance of limestones (dolomites). A prompt decision should be made to avoid further exposure of metals of concern to citizens in this overcrowded district of Tehran megacity.

Determining the main sources of pollution (MSP) in groundwater is crucial to improve water quality (WQ) status. Field studies were conducted in this research, where five sampling campaigns were carried out from 36 wells in the southern Tehran aquifer. In all samples, WQ parameters were measured and evaluated regarding the Iranian drinking water standard (IDWS). Finally, by using the principal component factor analysis (PCFA), the probable MSP in the aquifer were determined. The results showed that all ions, total hardness, and total dissolved solids were above the IDWS. To analyze the PCFA results, only the first four of twenty rotated principal factors (RPFs) that conserved a high percentage of the variance of the data (about 90%) were considered. The results of the first PRF revealed that the geological structure was the MSP in the aquifer. Furthermore, the second RPF was mainly affected by nutrients (nitrate and orthophosphate) and microbial parameters (fecal and total coliforms), indicating the importance of agricultural activities and sewage effluents as another MSP in the aquifer. Finally, the remarkable share of heavy metals and pH in formation of the third and fourth RPFs, respectively, reflected the role of industrial activities as a probable MSP of groundwater.

Nowadays, with the ever-increasing growth of the population and the development of various industries, we are experiencing an increase in man-made leachates such as urban solid wastes, chemicals, and wastewater. Generally, the groundwater in aquifers is contaminated by these pollutants seeping through the above-ground sediment. The vulnerability of groundwater to contaminants can be assessed, which means those areas with lower vulnerability can be distinguished from those areas with high vulnerability. Hydrogeological parameters are presented in a modified DRASTIC method which assesses depth to groundwater surface (D), recharge (R), soil media (S), topography (T), impact of vadose zone (I), conductivity of aquifer, hydraulic capabilities (C), and the effect of land use activity (L). This study aims at zoning the pollution potential of the Mashhad aquifer by using the modified DRASTIC method and GIS to assess the old and new landfill sites. The results show that new and existing (old) landfill sites for solid waste disposal in Mashhad site selections should be closed down due to their location in high vulnerability zones where the risk of groundwater pollution is high.

The present study was carried out in Haraz basin (Iran) that is located in south of the Caspian Sea. The goal of this study was to establish correlations amongst total suspended solids concentration (TSS) and turbidity with total pollutant concentrations to evaluate the dissolved and particle-bound concentrations of major toxic metals. It also aimed to validate TSS and/or turbidity measurements as proxies to monitor pollutant fluxes. Eight metals, namely nickel, lead, cadmium, copper, zinc, cobalt, arsenic and strontium were analyzed for dissolved and total concentrations in water at ten locations within the catchment. TSS and turbidity were also measured. Sampling campaigns were designed to cover both the rainy (December) and the dry (May) season within the basin. The robust relationship between TSS (202–1212 mg/l) and turbidity (63–501 NTUs) in both seasons warranted their interchangeable potential as proxies within the observed ranges. Total element concentrations were plotted in separate attempts versus TSS and turbidity for all locations and both events. Very good linear correlations were attained where the slopes represent the metals concentration on suspended solids and the intercept the dissolved concentration in water. The results achieved by these linear regressions were in very good agreement with independently measured values for dissolved concentration and concentrations on river bed sediments taken at the same locations. This demonstrates that turbidity and/or TSS measurements may be used for monitoring of metal loads if once calibrated against total concentration of metals. The results also revealed that in the lower Haraz catchment metal concentrations on suspended and river bed sediment were homogeneously distributed along the investigated river stretch. This is assumed to be due to intensive gravel and sand mining activities in the upper and middle part of the catchment.

Annually, a great volume of sediment and suspended particulate matters (SPMs) enters into the seas through estuaries. In the estuarine zone, metals present in SPMs may undergo conservative or non-conservative changes. In the present study, oxidation-reduction potential (ORP) as the most complex chemical parameter of open sea water and its relationship with the behavior of t metals in the estuarine area were investigated. Dissolved oxygen was used as a strong oxidant to increase the ORP. According to the absorption and desorption experiment, Mn and Cu are desorbed from SPMs during estuarine mixing. However, Zn and Pb are absorbed into the SPMs. In addition, the analysis results were indicative of the conservative behavior of Ni. The results of the three-step chemical partitioning of the SPMs revealed that Mn and Cu are desorbed from the SPMs physically, whereas Zn is absorbed into the SPMs chemically. Also, results showed that Pb is physically desorbed from the SPMs, while it is absorbed into SPMs chemically. All metals, except for Ni and Zn, whose reactions with the SPMs are not affected by an increase in the ORP, are affected by the escalation of this parameter.

بر خلاف شاخص های فاکتور جابه جایی MF و کد ارزیابی ریسک RAC که آن ها نیز نقش پیوندهای فلزی را در تفسیر آلودگی لحاظ می کنند، در شاخص جدید مستقیما سهمی از مخاطره به فازهای احیا شونده و اکسید شونده داده شده است که این مسئله در هیچ یک از دو شاخص مذکور دیده نشده است. به بیان دیگر در شاخص جدید پیوندهای فلزی که به شکل بالقوه قابلیت رهاسازی فلز در محیط را دارند نیز با تخصیص وزن های جداگانه در تفسیر مخاطره آلودگی موجود دخالت دارند. این مشخصه شاخص جدید امکان تفسیر واقعی آلودگی موجود فلزی به ویژه هنگامی که بخش چشم گیری از غلظت همۀ فلز در فازهای احیا شونده و اکسیدشونده جمع شده است را ممکن می سازد. وابستگی نبودن سطح مخاطره به غلظت کل در شاخص جدید سبب می شود تفسیری از مخاطره در سطوح مختلف غلظت کل ارائه شود. علاوه بر این توانایی شاخص در تفسیر مخاطره آلودگی فلزی فارغ از منبع تولید اعم از انسان ساخت و طبیعی نداشتن قطعیت های ناشی از تفکیک این دو نوع آلودگی را نیز کاهش می دهد.

In this study, arsenic concentration of Haraz River water at 20 stations and relative risk and hazard levels regarding ingestion and dermal exposure routes are evaluated. Furthermore, the quantitative threat caused by the consumption of Rainbow trout muscle from the area is also analyzed. The concentration of arsenic increases from upstream areas towards the downstream estuarine zone with a substantial rise in the central part. Arsenic-containing drainage discharged from the Central Alborz coal mine, hot spring spas, as well as municipal (Amol city) and agricultural (numerous rice paddies) land uses that become denser towards downstream are considered as major pollution sources. The inhabitants are not exposed to a significant hazard or risk regarding dermal exposure. However, for the oral ingestion exposure route, all 20 samples present hazard quotient values greater than unity and risk values greater than one in ten thousand. The results show that if the river water is used for drinking, a high-risk status would be imposed on consumers. Finally, the concentration of arsenic in muscle tissues of ten Rainbow trout fish samples was found to range from 0.48 to 1.30 μg/kg of dry weight which is below the allowed daily intake. However, if we consider that lots of other constituents in the total daily intake within the study area contain arsenic, estimated values may be interpreted as a trigger for further health threats.

Suspended particles in rivers can act as carriers of potentially bioavailable metal species and are thus an emerging area of interest in river system monitoring. The delineation of bulk metals concentrations in river water into dissolved and particulate components is also important for risk assessment. Linear relationships between bulk metal concentrations in water (CW,tot) and total suspended solids (TSS) in water can be used to easily evaluate dissolved (CW, intercept) and particle-bound metal fluxes (CSUS, slope) in streams (CW,tot = CW + CSUS TSS). In this study, we apply this principle to catchments in Iran (Haraz) and Germany (Ammer, Goldersbach, and Steinlach) that show differences in geology, geochemistry, land use and hydrological characteristics. For each catchment, particle-bound and dissolved concentrations for a suite of metals in water were calculated based on linear regressions of total suspended solids and total metal concentrations. Results were replicable across sampling campaigns in different years and seasons (between 2013 and 2016) and could be reproduced in a laboratory sedimentation experiment. CSUS values generally showed little variability in different catchments and agree well with soil background values for some metals (e.g. lead and nickel) while other metals (e.g. copper) indicate anthropogenic influences. CW was elevated in the Haraz (Iran) catchment, indicating higher bioavailability and potential human and ecological health concerns (where higher values of CSUS/CW are considered as a risk indicator).

The hydrochemical characteristics of groundwater in the southern parts of Tehran Province are considered. Twenty-three sampling stations were selected and major anions/cations, electrical conductivity and pH were detected. Sulfate and chloride were found as major anions, while no specific dominant cation was determined. More than half of the samples were found to be unsuitable for drinking purposes, due to high concentrations of anions/cations. Regarding agricultural use, almost all samples were classified as having high-risk levels of salinity, while for alkali hazard considerable risks were observed in most cases. Generally, an increasing trend of salinity is observed from northwest to southeast of the study area. Such increase may be justified by the adjacency of the Iran central desert and salt lake to the southern boundaries of the study area. Extended use of sulfate-containing fertilizers may also play a key role in justifying the high sulfate concentration in comparison to other anions.

Groundwater quality of Tehran city is considered in this study. Nine sampling stations were selected, and composite sampling campaign was performed in summer 2012. Groundwater sampled from northern stations appeared to have acceptable characteristics for agricultural and drinking uses. The southern station samples did not meet the required guidelines. Concentration of SO4 2−, Na+ and Cl− obey a sharp ascending trend southwards. Accordingly, the electrical conductivity of the last station at the very southern areas is more than fifteen times greater than that of the first northern station. Tehran city is located in a semi-arid climate and experiences long hot summers. High rates of evapo-transpiration within urban green spaces and agricultural lands facilitate the salinization phenomenon in root zones. As a result, excess irrigation water eases the consequent percolation into aquifers. Furthermore, saline water intrusion from salt marshes located down south of the city is an expected consequence of wells overpumping. Such case is especially remarkable in hot seasons when an increased urban water demand is observed. Remarkable sulfate concentrations in saline water are mainly justified by percolation of sulfate containing fertilizers which are broadly used by local farmers in an uncontrolled manner. Surface run-offs and municipal wastewater leakage may also trigger the salinization process.

Predicting natural phenomena like flood and drought and consequently presenting an appropriate solution for fighting such natural hazards in northwestern Iran is considered in this study through clustering the precipitation regime. To compare the reference period (past) with the simulated data, the statistics of daily precipitation in six stations of Ardebil, Ghazvin, Hamedan, Kermanshah, Sanandaj, and Tabriz, have been provided for a 30-year period (1961–1990) and compared with the simulated data of 2021–2050. The simulated data was generated by general atmosphere circulation model HADCM3, A1scenario and was downscaled using the LARS-WG model. The method for comparing precipitations was done based on clustering in the form of 5 clusters for all the stations and study periods. One of the results of this research is the greater concentration of precipitation for the cold periods of the year (winter and fall) and the increase of annual precipitation by the amount of 20.62 mm for future period. Furthermore, the normality of two coordinates of precipitation and cluster frequency percentage was evaluated. The outputs of this section demonstrate that the precipitations of cluster 3 which have the features of light rain with average intensity, fall on this normal line for most of the stations and study periods. On the other hand, precipitations of cluster 1 indicating very heavy and intense precipitations, have the most distance to the normal line in most cases. Therefore, the precipitations of the third cluster need optimal exploitation management while those of the first cluster need required risk and crisis management.

The Ahvaz oil field located in southern Iran has been identified as a possible point of elemental pollution, since elevated levels of metallic pollution (As, Cd, Cr, Ni, Cu, Zn, Pb and V) have been introduced to the adjacent environment through the oil excavation activities. The concentration of metals Cr, Ni, Cu, Pb and Zn are far below all reference values while that of As, Cd and V are remarkably above limits. Enrichment factor (EF) reports the mean waste status to be enriched by all three elements As, Cd and V while the Igeo values manifest the strongly polluted condition for Cd and moderately polluted for As and V. In order to quantify the association of metal concentrations with various Acid soluble, reducible, oxidizable and pseudo-total phases and consequently to estimate the potential mobility of existent metallic pollution, the sequential chemical partitioning technique was used for the samples collected from clean soil, drilling mud and wastage pit. According to the results achieved by chemical partitioning analysis, Cd seems to be mobile. Similar conditions exist for V with relatively lower risk level. Regarding As, the potential mobility is estimated to be low as a remarkable portion of bulk concentration (more than 70 %) is accumulated in the pseudo-total phase. Paying attention to the bulk and partitioning concentrations of three enriched elements in the drilling mud, it is concluded that the main cause of wastage pit contamination may be attributed to the nature of drilling mud utilized in excavation activities. Additionally, the geological texture in different depths may also play a role in this scenario.

Evaluating the metallic risky pollution of soil in the vicinity of National Iranian Lead and Zinc Company in Zanjan Province, Iran is considered in this study. Twenty-six composite samples were collected from the surface soil of the study area including two lead and zinc depots. Total concentration of elements lead, zinc, chromium, cadmium, cobalt, arsenic, iron and manganese were analyzed. To envisage a more realistic view of the environmental risks, anthropogenic and bioavailable fraction of total concentration values were also detected. Total concentration values of arsenic, cadmium, lead and zinc were higher than that of shale and mean earth crust. Bioavailable and anthropogenic fractions analysis showed that Cd may be considered as the most threatening bioavailable pollutant. Lead and arsenic were also introduced as elements of concern. Enrichment factor assessed As and Cd to be significantly and Pb to be moderately enriched in topsoil samples while pollution index categorized Pb in moderately polluted status. Hierarchical cluster analysis indicates a probable kind of analogy in origin, behavior and destiny of mentioned elements. Because of their remarkable biological and anthropogenic fractions in soil samples, current abandoned open-dumped depots are potential pollution sources within the area. Strict monitoring procedure should be performed to prevent further mobility of metallic pollutants toward food chain.

The purpose of this research is to simulate the impact of climate changes on the need for energy consumption in household cooling and heating systems using degree-day index. To this end, general circulation model has been applied to identify future climate changes and simulate degree-day values. The research findings show an increase of energy consumption for cooling in households in 2075. Also, with warm seasons prolonging and cold seasons shrinking in a year, the need for the continuous supply of energy consumption for air cooling and ventilation increases.

Organophosphate pesticides are compounds that are not only toxic to both humans and wildlife but also difficult to degrade under natural environmental conditions. In Iran, agricultural practices are strongly dependent on the use of pesticides due to climatic and soil conditions, thus posing a potential risk to groundwater quality standards. Evaluating the concentration of organophosphate pesticides namely diazinon, fenitrothion, dichlorvos, ethion, profenofos, malathion and azinphos methyl in water samples in May (low precipitation rate), December (high precipitation rate) as well as the concentration in sediments along the Haraz River is taken into consideration in this study. Generally the pesticides concentration in water samples are relatively higher in May in comparison with that in December; this fact may be due to two major reasons: the first reason is attributed to the prompt raining after the treatment period of most orchards and dry farming lands that will terminate in more wash out of such pesticides towards the branches and main river channel, while the second reason may be considered as the less river water dilution rate in May because of lower precipitation rate. Furthermore, the relatively higher concentrations in downstream stations may be contributed to more intensified agricultural (specially rice paddies), urban and rural land uses in this region in comparison with upstream areas which contain mainly dry farming, grazing lands and orchards with relatively lower loads of pesticides. Additionally, as the Henry’s law constant of all pesticides considered in this study are relatively low, volatilization may not be regarded as an important route of dissipation. Diazinon, azinphos methyl and dichlorvos showed the highest water concentrations in comparison with other pesticides that may be justified by their extended use within the basin during last decades. Based on the chemical properties as well as remarkably higher values in sediment samples in comparison with water ones, it is concluded that the two pesticides, ethion and fenitrothion, persist in the environment due to non-degradable tendencies. Although the concentration of mentioned pesticides is not so high in the water samples, more precautions must be considered in their future use. Regarding the sorption coefficient variation alongside the river, the higher values in upstream and central parts may be attributed to the higher potential of different types of erosion regarding deeper slopes and also sand, gravel and carbonate mining activities at the banks and also river bed in such regions which is considered as an anthropogenic disturbance. In case of central parts, in addition to mentioned reasons, the existence of coal outcrops in the geologic texture of the study area may also be considered as a key role in augmentation of the sorption coefficient. Finally, the dominant clayey and loamy soils containing more organics may be attributed as the major reason of sorption tendency in downstream.

Hydrochemical quality of groundwater in an aquifer in central Iran adjacent to central Kavir desert was analyzed in this study. The dominant type of groundwater in the area is Na + K_Cl + SO4 which is mainly different from the common type of fresh waters in Iran (Ca_HCO 3 ). The spatial distribution of anions and cations as well as EC obeys an increasing pattern eastwards. Due to high concentrations of SO 4 2− , Cl − , K + and Na + all of the water samples are not categorized in suitable ranges for drinking use. Regarding agricultural use suitability of regional groundwaters, except for 4 samples in central parts of the study area which show high salinity hazard, all other samples are absolutely not applicable for agriculture due to extremely high values of EC. Illegal groundwater pumping mainly for regional agricultural use during recent years has caused groundwater quality degradation due to saline water intrusion from eastern areas (central Kavir desert and salt lake) and connate water upcoming from deeper aquifers. As the main use of water in the study area is contributed to agriculture, implementing modern mechanized irrigation techniques accompanied by planting crops with low water demand and high tolerance against salinity may be recommended.

The Haraz River flows northwards through the Iranian Alborz mountains in the central region of Mazandaran province and empties into the Caspian Sea. This area has been a rich source of minerals from times immemorial. About 45 mines (coal, limestone, sand and gravel, etc.) have been operational for the last eight decades. Towards the estuary, the river receives a discharge of industrial, agricultural and urban wastes. Eight sediment samples from the Haraz River and its main tributaries were collected and analyzed for base metals as well as Sr and Fe. The chemical partitioning of metals (Cu, Zn, As, Cd, Pb, Fe, Ni, Cr, Co and Sr) in each sample was determined in four fractions (acid-soluble, reducible, oxidizable and residual). The total content of each metal was also determined. The results showed relatively higher concentrations of Cd, As, Sr and Pb in comparison to that of shale. However, based on the chemical partitioning of metals, it is found that Pb, Co, Cd and Sr are the most mobile metals. In spite of the high As concentrations in sediments, it is not likely that this element is a major hazard for the aquatic environment, since it is found mainly in the residual fraction. Cadmium is the metal that showed the highest percentages in the acid-soluble fraction (the most labile) and the lowest in the residual fraction. However, Fe, Cr and Ni are present in the greatest percentages in the residual fraction, which implies that these metals are strongly linked to the sediments.

Sungun mine is the largest open-cast copper mine in northwest of Iran and is in the primary stages of extraction. The influence of mining activity on the quality of regional groundwater has been taken in to consideration in this study. Accordingly, sampling was done from 22 springs in the study area. The concentrations of major anions and cations as well as Al, Cu, Cd, Cr, Fe, Mn, and Zn were determined for all 22 spring samples in mid-August 2005. The results showed that the concentrations of most of these elements were below the USA Environmental Protection Agency (EPA) limits; however, Al and Fe concentrations are considered to be more than limits in a couple of samples. Despite the fact that geological formations are highly weathered and fractured, the dissolution of minerals within the study area is low. This may be justified by the relatively high alkalinity of local underground water which keeps metals in solid phase and does not let them enter dissolved phase. Additionally, this may be attributed to the high velocity of groundwater flows, which do not give enough time for minerals to dissolve. Correlation coefficients among water chemistry components were determined and the weighted-pair group method was chosen for cluster analysis. Accordingly, high correlation among Al, Fe and Cr, Cd ,and Cu, sodium absorption ratio (SAR) and Na as well as total hardness (TH), Ca, and Mg were observed. The chemical characteristics of water compositions on the basis of major ion concentrations were evaluated on a Schoeller and Piper diagram. Accordingly, the dominant type of water in the region is considered to be Ca-HCO3 (calcium-bicarbonate type). However, this type of water is also rich in Na, K, and especially Mg. Regarding Schoeller diagram, the current status of local underground water is good for drinking purposes. By commencing mining excavation with designed capacity in near future, the minerals will come into contact with air and water resulting in dissolution, especially in ponds, which, in turn, will increase the concentration of toxic metals in groundwater. Considering future uses of this water including for drinking, irrigation, industrial purposes, etc., precautions must be taken in to consideration.

In order to evaluate the feasibility of implementation of horizontal-flow roughing filtration for drinking water treatment a pilot was designed and run at the bank of Zayandehroud river near the village of Chamkhalifeh. Pilot running was performed in summer 2003 (July, August and September), when the quality of river water was in relatively worst condition. The filter is comprised from three different parts which are separated with perforated baffles. Each compartment is filled with some local sand and gravel considering a special decreasing size regime. The overall function of the filter in removing turbidity and total suspended solids is acceptable. Additionally, iron, manganese and color and coliform removal are also been covered to some extent. Achieved results in this study shows that horizontal-flow roughing filtration may be considered as a packed, low-cost and efficient pretreatment process incase surface water is used as water supply for treatment. Furthermore, when small scale societies are considered and when no major pollutants exist in the water supply as the case in this study_ this system may be posed as a total treatment system, in which treated water exited from the filter may be sent to distribution network after a simple post chlorination.

Aras water basin is located in northwest of Iran. Sungun mine which is the largest open-cast copper mine of Iran is located in this region and is in the primary stages of extraction. The influence of mining activity on the quality of regional surface water has been taken in to consideration in this study. Accordingly, sampling was done from 5 local streams in the study area. In order to consider the effect of flow quantity on the amount of different parameters, sampling was done in July and November 2005 when the local streams had the minimum and maximum flow rate respectively. The concentrations of major anions and cations as well as As, Mo, Al, Cu, Cd, Cr, Fe, Mn and Zn were determined. The results showed that the concentrations of metallic ions like aluminum, chromium, copper, manganese, molybdenum and iron in samples collected in July are above USEPA (Environmental Protection Agency) limits; however, mentioned concentrations are lessened remarkably in the samples collected in November. This fact is justified considering dilution of ions concentration via more amount of water in November. The chemical characteristics of water compositions on the basis of major ion concentrations were evaluated on a Schoeller and Piper diagram. Accordingly, the dominant type of water in July and November is considered to be Ca-HCO3 (calcium-bicarbonate type). Regarding Schoeller diagram, despite relatively high concentration of calcium, the current status of local surface water is acceptable for drinking purposes. By commencing mining excavation with designed capacity in near future, the minerals will come in to contact with air and water resulting in dissolution, especially in ponds, which, in turn, increases the concentration of heavy metals in surface water. Considering consequent uses of this water including drinking, irrigation, industrial, etc. precautions must be taken in to consideration.

During the recent decades, the increasing trends in nitrate ion concentration in ground water sources have meant more research to find effective procedures for the prevention of even more water contamination by nitrogen sources. In this study a pilot was designed to examine the application of biological method for eliminating nitrate from the water of well No.903 of Mehrabad Airport, Tehran, Iran. Design, installation and running processes were done from April to November 2003. A fixed biological bed containing five-centimeter trunk pipes 16 mm in diameter were installed in the reactor and the system was operated with upflow current. Instead of Methanol, Acetic acid was used as the carbon source because of its easier acceptance by the public, lower price and availability as well as easier storage. The pilot was run in different hydraulic retention times from 48 h up to one hour. Considering economical, operational and maintenance factors, retention time of 2 h was determined to be optimum, in which 77% nitrate removal was achieved. Considering a ratio of 2 for COD/N, inlet COD of about 140 mg/L and the optimum retention time, COD removal of about 80% is also accomplished in this process. The amount of nitrite concentration, pH values, COD and turbidity is also evaluated versus different hydraulic retention times.

Regional distribution of quantitative risk and hazard levels due to arsenic poisoning in some parts of Iran’s Kurdistan province is considered. To investigate the potential risk and hazard level regarding arsenic-contaminated drinking water and further carcinogenic and non-carcinogenic effects on villagers, thirteen wells in rural areas of Qorveh County were considered for evaluation of arsenic concentration in water. Sampling campaign was performed in August 2010 and arsenic concentration was measured via the Silver Diethyldithiocarbamate method. The highest and lowest arsenic concentration are reported in Guilaklu and Qezeljakand villages with 420 and 67 μg/L, respectively. None of thirteen water samples met the maximum contaminant level issued by USEPA and Institute of Standards and Industrial Research of Iran (10 ppb). The highest arsenic concentration and consequently risk and hazard levels belong to villages situated alongside the eastern frontiers of the county. Existence of volcanic activities within the upper Miocene and Pleistocene in this part of the study area may be addressed as the main geopogenic source of arsenic pollution. Quantitative risk values are varying from 1.49E-03 in Qezeljakand to 8.92E-03 in Guilaklu and may be interpreted as very high when compared by similar studies in Iran. Regarding non-carcinogenic effects, all thirteen water samples are considered hazardous while all calculated chronic daily intakes are greater than arsenic reference dose. Such drinking water source has the potential to impose adverse carcinogenic and non-carcinogenic effects on villagers. Accordingly, an urgent decision must be made to substitute the current drinking water source with a safer one.

The problem of leachate treatment is something critical for the landfill of Tehran (Kahrizak). Natural Leachate treatment is a way to help the environment rehabilitate itself, and lessen the threats of pollution for alive habitats. It produces an appropriate situation for existing plants and animals to keep on living and also it may help other existences to find their new habitat in the site of rehabilitated landfill. One of the biggest problems in Tehran is lack of water. Therefore it can help using recycled water for irrigation and keep microclimate of the region alive. Designing a good region to recycle the leachate naturally and absorb the contaminants of soil and water in the originate site, is a huge responsibility for environmental designers.

The Haraz River is one of the most significant rivers in the southern Caspian Sea basin. Towards the estuary, the river receives discharges of industrial, agricultural, and urban wastes. In the present investigation, bulk concentrations of Cu, Zn, As, Cd, Pb, Fe, Ni, Cr, Co, and Sr in Haraz River (Iran) bed sediments were measured from several sample locations. In addition, association of studied metals with various sedimentary phases was assessed to determine the proportions of metals in different forms. The intensity of sediment contamination was evaluated using an enrichment factor (EF), geo-accumulation index (Igeo), and a newly developed pollution index (Ipoll). Both EF and Igeo formulae compare present concentrations of metals to their background levels in crust and shale, respectively. In a specific area with its own geological background like Haraz River water basin where naturally high concentrations of metals may be found, such a comparison may lead to biased conclusions regarding levels of anthropogenic contamination. Accordingly, chemical partitioning results are substituted for the mean crust and shale levels in the new index (Ipoll). The Pearson correlation coefficient between the anthropogenic portion of metallic pollution in Haraz river-bed sediments with Ipoll showed much more value in comparison with those of geochemical accumulation index and enrichment factor. The order of metals introduced by anthropogenic activities are as follows: Sr > Pb > Co > Cd > Zn > Cu > Ni > As > Cr > Fe. The results showed relatively higher concentrations of Cd, As, Sr, and Pb in comparison with those of shale. However, based on the chemical partitioning of metals, it is found that Sr, Pb, Co, and Cd are the most mobile metals. In spite of the high As concentrations in sediments, it is not likely that this element is a major hazard for the aquatic environment since it is found mainly in the residual fraction. Also, Fe, Cr, and Ni are present in the greatest percentages in the residual fraction, which implies that these metals are strongly linked to the sediments.

Recently, increasing attention has been paid to the environmental impact of solid waste in Iran. Consequently, solid waste management has become a remarkably important issue. Solid waste comprises a wide range of materials and comes from a variety of sources. Having a population of about 10 million (about 1/7 of Iran's total population), Tehran is among the most populated capitals in the world. With 22 different districts, this city generates approximately 7,000 metric tons of municipal waste per day that culminates in a total of 2.5 million tons annually. If no reduction strategy on the waste stream is implemented, this huge amount of waste will be buried in Kahrizak (the exclusive landfill site of Tehran). Land and underground water resource degradation in the vicinity of the landfill site-as well as disease outbreaks in the area surrounding the site may be considered alarming warnings for further catastrophic consequences of uncontrolled waste dumping. In this study, the composition of Tehran's solid wastes is analyzed. In order to physically analyze waste generated, waste sampling was carried out by trained workers of the Tehran organization of waste recycling and compost in 2004 for 10 successive days in the middle of each of four seasons. As a result of the study, some practical recommendations are made to reduce the waste stream load directed toward the land. Furthermore, this study evaluated people's concern about the fate of the waste they generate. According to the data collected in a survey, citizens' participation is not remarkably high, but even the modest cooperation recorded may cause a great benefit if extrapolated to the whole city. By virtue of sharp decreases in the cost of total waste collection and transport, as well as the benefits of land and underground water resource preservation, separation of wastes at their source by individual households makes economic sense.

Iran is one of 27 countries that are likely to face increasing water shortage crises between now and 2025 unless action is taken to reduce currently high-per-capita urban water consumption. Accordingly, consumption control in the mega-city of Tehran will be an invaluable achievement. A study of Tehran water consumers has determined that household consumers are responsible for 70 percent of the total consumption. Keeping that figure in mind, the authors set out to assess rates of consumption by water fixtures, with an emphasis on household users, and to examine the effects of installing subcounters and reducers. They selected an apartment complex in which it was possible to install water subcounters for each unit. The first step was to evaluate resident attitudes. Block 3, which had 10 units, was selected to cooperate with the project. The second step was to install counters for all 10 units to determine consumption by different fixtures. (The counters were installed in kitchens, in bathrooms, on toilets, on washing machines, and on flash tanks). In the next step, data entry forms for fixture consumption were completed for a period of 10 days. Then single-handle faucets and reducers were installed, and the outcomes were logged for a period of 10 days. Counter readings were performed by the volunteer residents or by educated personnel every 24 hours, and the total volume of inside consumption was compared with the consumption registered by a base counter placed outside each unit. In the course of the project, the consumption per capita was calculated every 24 hours to yield a real and unbiased model that is applicable to city of Tehran. The results showed a total reduction in water consumption of about 20 percent. Thus, with suitable planning and application of cultural and technical methods, it is possible to optimize consumption in Tehran in the near future.

The Caspian region (including the Golestan, Mazandaran, and Guilan provinces of Iran) occupies 58,678 square kilometers (22,651 square miles) and has a population of 6,270,192, according to the census of 1996. This part of Iran is attractive to tourists because of its proximity to the Caspian Sea. In addition, the region boasts invaluable forests and grasslands, and is the exclusive producer in the country of key agricultural crops like rice and tea. The lack of systematic solid waste management has put this region on the edge of irreparable environmental damage. The large number and dispersion of open-dumping landfills, as well as the faded role of functional elements like waste minimization and processing, have sped up the environmental deterioration. This article evaluates the current status of solid waste management in the Caspian region and suggests practical alternatives. As a result of a field and desk study, the authors offer some instructions for separation of putrescibles, paper and cardboard, plastics, and so forth. Finally, after considering all aspects of the environmental impact assessments for different alternatives, the authors recommend the construction of two compost-producing facilities in Golestan province with a combined capacity of 500 metric tons per day and a total cost of $60,000, and four incineration sites in southern and southwestern parts of the region (Mazandaran and Guilan provinces) with a total capacity of 2,000 metric tons per day and total cost of $75 million.

To determine the most appropriate composting process in an active municipal solid waste system, an experiment was carried out using a nested design method with three aeration rates. During each aeration rate, parameters such as temperature, pH, EC, carbon-to-nitrogen ratio, NO(3)-N, nitrogen, potassium and phosphorous were measured and the efficiency of different composting processes was evaluated. The result of this study showed that the lower and medium aeration rates had a significant impact on nitrogen, carbon-to-nitrogen ratio and temperature profile, while higher aeration rates led to higher EC values. Furthermore, the thermophilic phase lasted 13, 9 and 4 weeks for the aeration rates of 0.4, 0.6 and 0.9 L min(-1)kg(-1), respectively. Accordingly, it was concluded that starting at a rate of 0.6 L min(-1)kg(-1) during first 2 months (about 9 weeks) of the process and continuing at a rate of 0.4 L min(-1)kg(-1)until the end of composting process would result in lower energy consumption.

Kurdistan Province, with an area of 28,203 square kilometers, is located in a mountainous area in the western part of Iran. From 1967 to 1997, the urban population in the major eight cities of the Kurdistan Province-namely, Baneh, Bijar, Divan Darreh, Saghez, Sanandaj, Ghorveh, Kamyaran, and Marivan-increased from 102,250 to 705,715. The proportion of the population residing in urban areas increased 90 percent during this period. In most of the cities, solid waste handling remains primitive, and well-organized procedures for it have not been established. Traditional methods of disposal, with marginal inclusion of modern conveniences, appear to be the common practice. In general, the shortcomings of the prevailing practices can be summarized as follows: The municipal solid waste management systems (MSWMSs) in this province include unsegregated collection and open dumping of municipal solid wastes. Separation of municipal solid waste in this province is in the hands of scavengers. The MSWMSs in this province lack essential infrastructure. Thus, design and implementation of modern MSWMSs in this province are essential. Principal criteria for and methods of implementing these systems are as follows: (1) rationally evaluating all functional elements so that they operate in a steady-state or equilibrium manner; (2) creating all support elements for the MSWMS in each city; (3) introducing gradual privatization of MSWMS activities; (4) creating guidelines, regulations, and instructions for all elements of MSWMSs; and (5) giving priorities to source separation and recycling programs. This paper reviews the present status of MSWMSs in eight major cities of Kurdistan Province and outlines the principle guidelines and alternatives for MSWMSs.

The foremost role of a building is to assure the comfort of its occupants. The thermal comfort of a building depends on the outdoor climate and requires a demand in energy for heating and cooling. In this paper, demand of energy (heating/cooling) in the buildings is discussed in Douala, Cameroon. Daily data of the last 40 years coming from five weather stations of Cameroon have been studied. Some forecasts have been carried out with 14 GCM models, associated to three future climate scenarios B1, A2, and A1B. However, only INCM3 of General Circulation Model (GCM) and A2 scenario was used. Energy demand in buildings is valued by HDD (heating degree day) and CDD (cooling degree day) indices. Obtained results show that the temperature evolves more quickly in dry season than in rainy season in Douala. Climate rise indicates an increasing demand of energy in the buildings for cooling. Global Douala heating shows a definite effect on outdoor comfort. From 2045 to 2075, the demand of energy for cooling will be superior to 50%. The total demand in energy for heating in the buildings is estimated to be 67.882 kcal from 1970 to 2000 and will be around 67.774 kcal from 2013 to 2043.

Sludge, which is produced as a by-product of all treatment processes, has considerable potential as a fertilizer and soil conditioner. Many authorities now discharge the sludge after treatment directly to agricultural land in liquid form, while some others dewater and dry it first. In either case, with proper marketing, it is generally possible for an authority to earn revenue by this means, although it is rare for the income to cover all the cost involved. In some industrial sludge the total solid concentration may range between 2000-100000 ppm and it is reported that more than 6000 waste water treatment plants use the conventional sludge drying sand bed. An experimental investigation was carried out to assess the efficacy of solar energy for drying of sludge from pharmaceutical industrial waste over a sand bed covered with glass as compared to the conventional sludge drying over a sand bed as well as to reduce environmental pollution The two drying beds are constructed in 12 cm thick brick wall with cement mortar and has an effective area of 0.5 m (2). On the 0.4 m thick layer of gravel and send the sludge layer from pharmaceutical industry was deposited. The Solar Sludge Drying Sand Bed (SSDSB) reduced drying time by about 25-35% as compared to the Conventional Sludge Drying Sand Bend (CSDSB). The rate of evaporation from the sludge surface and hence the drying was a function of solar radiation. The condensed evaporated water was qualitatively analyzed for probable reuse.